Chemical solvent effects during reactions in supercritical fluid solvents

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:6859498

Townsend, S H

Neat pyrolysis and reaction in supercritical water were investigated for a collection of aromatic ether (phenethyl phenyl ether, dibenzyl ether, benzyl phenyl ether and phenyl ether) and fully-hydrocarbon (diphenylmethane, 1,2-diphenylethane and 1,3-diphenylpropane), model compounds, as well as one heterocyclic ether (dibenzofuran), toward gaining an understanding of the reactions of biomass and coal in supercritical fluid solvents. Analysis of the reaction products and the derived pathways and kinetics from the neat pyrolysis of each model compound provided a baseline with which the results from its reactions in water could be compared. Orthogonal sets of experiments separately examined the impact of reduced water loading on the rates of reaction and on product selectivities. This approach enable the discovery that, as a supercritical fluid extraction solvent, water was capable of participating as a reactant during the solvolysis of certain chemical moieties. A hydrolysis pathway was elucidated that operated in parallel with the thermal pathways of neat pyrolysis for phenethyl phenyl ether, dibenzyl ether and benzyl phenyl ether. 1,2-Diphenylethane and 1,3-diphenylpropane underwent only pyrolysis, and phenyl ether, diphenylmethane and dibenzofuran were all found to be thermally stable, under the conditions explored by this investigation. Kinetics analysis of the experimental data for phenethyl phenyl ether and dibenzyl ether enable decoupling of the rate constants governing pyrolysis and solvolysis. These results were extended to describe the reactions of a class of compounds having a saturated carbon to which was attached a heteroatom-containing leaving group.

• Research Organization: Delaware Univ., Newark, DE (USA)
• OSTI ID: 6859498
• Country of Publication: United States
• Language: English

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